Electric ore-furnace.



J. A. WARD.

ELECTRIC ORE FURNACE.

APPLICATION FILED APII. I2. IQII.

1,252,685. @rented Jan. 8,1918.

J. A. WARD.

ELECTRIC ORE FURNACE.

APPucAUoN man APR.12,1917.

oo H1 w3. YT @DE IH mJy www E AME Ew LIL l2 1 0 t d nl UNITED STATES PATENT OFFICE.

JOI-IN A. WARD, F SPOKANE, WASHINGTON, ASSIGNGR 0F ONE-FOURTH TO E. S. CAMPBELL, ONE-FOURTH TO W. A. RIDGEW'AY, AND ONE-FOURTH TO HENRY SORENSEN, OF SPOKANE. VASHINGTON.

ELECTRIC ORE-FURNACE Application led April 12, 1917.

To all whom t may concern Be 1t known that I, JOHN A. VARD, a citizen of the United States7 residing at Spc` kane, in the county of Spokane and State of Nashingtom have invented a new and useful Improvement in Electric Ore-Furnaces7 of which the following is a specification.

This invention relates to improvements iu electric ore furnaces, and has for one of its objects to provide a means for closely and continuously regulating the heat of electric coils used in such furnaces.

A further object of the invention is to provide a means for using the ore body itself as the electric heating element.

A further object is to utilize the heat generated by the controlling device, thus eliminating a usual source of waste in electric furnaces.

IStill further objects and features of the invention will be more fully described in connection with the accompanying drawings and will be more particularly pointed out in and by the appended claims.

ln the drawings:

Figure l is a section through the furnace showing the arrangement of carbon contacts and the arc control.

Fig. 2 is a part section taken on line B-B of Fig. 1, and shows the method of taking off the metal and the slag from the furnace.

Fig. 3 is a section of the inner wall of the furnace showing a modified form of construction with coils embedded.

F ig. et is a section showing detail of arc carbon holder.

Fig. 5 is a wiring diagram showing diagrammatical arrangement of two furnaces connected on one circuit.

Fig. 6 is a side elevation of a switch used in the connections of Fig. 5.

Fig. 7 is a plan view of the same switch.

Fig. 8 is an elevation showing arc adjusting mechanism.

Fig. 9 is an enlarged view of one of the clutches shown in Fig. 8.

Fig. 10 is an enlarged side elevation of the same clutch.

- Fig. 11 is a section of the furnace Crucible showing a modified construction.

Like numerals refer to the same parts throughout the various iigures of the drawings.

Describing in detail, in Fig. 1, l is the shaft of the furnace proper. This is where Specification of Letters Patent.

Patented Jan. S, 1918.

Serial No. 161,456.

the progressive heating of the ore takes place or the low temperature and roasting as the case may require. The bosh or reduction portion of the furnace is the Zone 2, and f3 indicates the furnace Crucible or the portion of the furnace where the molten metal accumulates. This portion of the furnace has for its base a conducting plate -l-. rlhe lining 5 of the bosh and shaft of the furnace is composed of a refractory and non-conducting material, and through this, inserted at regular intervals are conductingpencils 6. These lit snugly in the` openings .7 of the furnace lining 5 and project far enough into the furnace to make electrical contact with the ore body. Pencils 6 also pass through openings S in the outer wall 9 to permit of their insertion or withdrawal from the outside. Pencils 6 are arranged in diametrically opposed pairs, cach pair being' connected together electrically by wires 13 and also connected to one side of each of the switches 1d. These switches let are single pole, single throw switches, the other sides of which are all connected together by a bus wire 15. Trapped around the furnace wall 5 is a resistance coil 10 with its terminals taken out at 11 and 12. Below the crucible 3 are thc arc forming contacts 1G and 17. These are slidablv supported on the rollers 1S and are normally held together by gravity. They pass easily through openings 19 in the outer wall 9. The rollers 18 are in turn supported by brackets 2O fastened to the outer wall by bolts 21. Above the arc formed between contacts 1G and 17 and between it and the base plate -L is inserted the wall 22 composed of a refractory and nonconducting material. Surrounding the furnace proper is an air space 23 provided as a means of heat insulation. The top or receiving part of the furn nace is shown at 24. Openings 25 are provided through the outer wall 9 for the purpose of watching the temperature of the coil 10. In these openings are inserted mica sheets 26 to permit vision, and at the saine time Vprevent the escape of heat.

In Fig. 2 an opening 27 and its surrounding refractory wall 28 is provided, slightly inclined to the horizontal, for the purpose of removing slag. Numeral 29 is a refining Crucible which is arranged for the treatment of certain ores. Its base 30 and general design is of such a nature that an auxiliary source of heat may be applied to its contents back to the source l0. The carbons forming the arcs being held togetherl by gravity to permit the circuit to be complete. rEhe solenoids 47 and 47; are designed for the correct current for the system to which they adapted, and when the carbons are in contact the currrent is of such a strength as to cause the armatures G/-l and 64; to be drawn up into the solenoids. rEhe armatures through the pins G5 and 65 engage the clamp stems G6 and 66 and thus tip respectively the clamps G7 and GT, bringing the knurled surfaces in contact with the carbons and thus causing the carbons to follow the motion of the armatures Ga and Gil and so be drawn apart. This lengthens the arc and reduces the current flowing, which in turn releases the armatures 3f-land G-l, allows the clamps 67 and 67 to assume their normal position, and thus allows the carbon pencils 16 and 17 to fall by gravity. The carbon pencils 16 and 17 are tipped very slight-ly to the h rizontal and the pull of gravity is just sufficient to overcome the friction of the different rollers. ln operation therefore, the carbons come to a position in equilibrium which maintains an even flow of current throughout the circuit. rit any time a very slight increase in the amount of current flowing produces a motion of the solenoid armatures 6i and 64 and thus, as has just been described, immediately reduces the current. Dash-pots may be provided to dampen the movement of the armatures. These are not shown on the accompanying drawings because their use is standard, as is the general method of adjusting the carbons of an are by means of solenoids.

The current flowing as described is kept constant in the coils 10 and 10 and the ore gradually brought up to most any desired temperature, depending upon the design of the furnace. If a greater temoerature is desired at one lportion oA the furnace than at another, .i modification of the lines of the wall or of the winding of he coils will effect this result. lt is often desirable to use the ore body itself as the heating element, malring it part of the electric circuit. For this purpose Jthe switches 42 and 43 are thrown in the opposite direction to make Contact with the clips 51, 52, 55 and 56. This opera tion throws out the coils 10 and 10 and throws in circuit in their place the circuits which are completel from the base plate 4 through the ore to one or more of the pencils (3, and from the base plate lt through the ore to one or more of the pencils 5. The s 'itches used for this operation are constructed as shown in Figs. 6 and 7 so that at no time the circuit completely broken, the circuits through the ore being closed slightly before the coil circuits are opened. The pair of pencils nearest the base of the furnace in cach case will be the ones to receive the main portion of the current. ln case the current thus flowing is greater than desired, the lower small switches 14 and 14; connecting these pencil pairs are opened and the current then flows to the next higher pair of pencils. rl`his pro Iess can be repeated as often as desired until the current flowing is of the desired amount.

in the operation of one furnace only, the coil which would be used on the second furi nace is wound on the upper part of the one furnace in use, and the connection diagram is otherwise the same as for the vtwo furnaces. ln each individual furnace as the ere melts it flows into the crucible as at 3 in liig. 1. Here it is kept hot by one or more arcs formed, as previously described, and pos. tioned underneath and close to the Crucible base. ln this way the energy used up in the regulating device (that is, in the arc or arcs) is u lined and the entire process becomes more efficient than in the ordinary method where a rheostat exterior to the furnace is used .for the regulating means. For certain methods of construction it is necessary to lengthen the carbons, and a means for doing been described and is shown in Fig. ethods of adjusting arc forming contacts have been in use for many years; one forni of doing this is shown in Fig. 8 where strengthening `thc fields of the solenoids di' and ai causes their armatures (il and (idf to be drawn in, which movement, through a tilting of the clamp members G7 and G7 causes the arcs to be drawn apart in the manner as hcreinbefore described.

'lihile l have described one specific embodiment of my invention, l do not wish to be limited theret except for such limitations as the claims may import.

l claim:

1. i method of controlling the current flowing through the heating element of an electrical heater by introducing in the cir cuit a pair of adjustable arc forming electrodes, said electrodes being exteriorl to the heater itself and thus having independent ieat radiating' properties.

2. A method of controlling the current flowing through an electric circuit forming the heating element in an ore furnace by inserting arc forming electrodes in said circuit, exterior to the furnace and by providing means of automatically adjusting the spacing of said electrodes so as to oppose and counteract tendencies toward current variation.

3. A method of controlling the heat in an electric ore furnace by means of an adjustable arc, independent of and separate from the furnace, but inserted at some point in the electric heating circuit of the furnace so that the current flowing in said circuit is dependent upon the position of the electrodes of the arc.

te i

la ln an electric ere furnace, a heating' element, a plurality of a rc forming contacts in series with said heating element, one or more solenoids in series with said heating element and with said are forming contacts, mechanical means whereby a change in the field strength of the solenoids produces a corresoonding change in the position of the arc forniin' contacts.

in electric heating system for ore furnaces comprising the combinati n cfa coil of suitable resistance wire, a pair of arc forming contacts adapted to be placed in series with the resistance wire and one or more selen in series with said are forming contac id said resistance wire, said solenoid or smenoids having movable armatures mechanically connected with the arc forining contacts so as to regulate the length of the arc and thereby regulate the temperature of said coil of resistance wire.

tl. ln an electric ore furnace, an electric heating coil of wire surrounding said furnace, a series of conducting pencils piercing the furnace wall so as to be in electrical contact with ore contained in said furnace, a conducting plate so positioned at the baseof said furnace as to be in electrical ccntact with furnace contents, and a switch so constructed as to provide means for opening a circuit through said coil of wire and for closing a circuit through the ore contents of said furnace from said base plate to said conducting pencils, said closing being effected slightly before the opening of said wire coil circuit.

7. ln an electric ore furnace, an electric heating coil of wire surrounding said furnace, a series of conducting pencils piercing the furnace wall so as to be in electrical contact with ore contained in said furnace, an annular conducting band surrounding the Crucible of said furnace and so pasitioned as to be in electrical contact with furnace contents and a switch so connected and so constructed as to provide means for opening a circuit through said coil of wire and for closing a circuit through the ore contents of said furnace from said annular conducting band to said ccnducting pencils, said closing being effected slightly before the opening of said wire coil circuit.

S. in an electrical ore furnace, a heating circuit, a plurality of adjustable are forining contacts connected in series therewith and positioned exterior to the furnace, means for automatically spreading` Said eontaets with any increase of current in said circuit so as to counteract said current increase and thus to effect a regulation. of teniperature.

9. ln an electric ore furnace, a main heating element consisting of coil of wire surrounding the furnace, a plurality of adjustable arc forming contacts in series with said coil of wire, and means for automatically adjusting said contacts to effect a regulation of Vthe temperature of said coil of wire.

l0. ln an electrical ore furnace, a main heating element consisting of a coil of wire surrounding the furnace, a plurality of adjustable arc forming contacts in series with said coil of wire, means for automatically adjustin@` saidL contacts to effect a regulation of the temperature of said coil of wire, and means for utilizing the heat generated by the arc or arcs formed between said contacts in aiding the process of ore reduction.

ln testimony whereof, l hereby ailix my signature in the presence of two witnesses,

JUHN El. ivf/XRD. lllitnesses G. M. Spaans, H. R. SiMoNDs.

@epics of' this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

*Washington D. C. 

